Polymer manufacturing process

ABSTRACT

Embodiments relate to a relatively rapid transesterification process including transesterifying condensation polymers such as polyethylene terephthalate (PET), or other polyesters used in commerce, with a modifying monomer mix containing other monomers to manufacture new polymers containing the pre-condensed moieties. The process preferably only involves transesterification as a reaction mechanism. The process preferably produces a rapid buildup of molecular weight and/or polymer uniformity by the high temperature transesterification of the condensation polymer with the modifying monomer mixture. The process can be performed in any suitable vessel including an extrusion line, and it has the advantage of greatly reduced cycle times over currently used condensation polymer utilization processes such as the recycling of PET into other materials.

BACKGROUND

1. Field of the Invention

Embodiments relate generally to a transesterification process involvingat least the transesterification of polyester terephthalate (PET) orother polyesters used in commerce, with a modifying monomer mixture toproduce new polymers. The new polymers so produced are useful, forexample, as adhesives in the manufacture of a variety of carpet productsand other textiles, or for other adhesive uses.

2. Description of Related Art

Esterification typically includes the condensation of organic carboxylicacids and alcohols to yield ester linkages. Polyesters are made whenmultifunctional carboxylic acids are reacted with multifunctionalalcohols to yield polymers containing repeating ester units. Polyestershave become important polymer components used in a variety ofindustries.

The esterification reaction required to manufacture polyester polymersusually takes a great deal of time compared to other polymerizationreactions. For example, a typical aromatic polyester of moderatemolecular weight can require between 12 and 24 hours to finish whereasan aromatic styrene polymer prepared by free radical polymerization cantake as little as one hour to complete. There are several reasons forthis increased duration. One reason is that the temperatures requiredfor esterification are much higher on the order of 200 to 250 degreesCentigrade than those of other reactions such as free radicalpolymerization which require temperatures of only 70 to 100 degreesCentigrade. Another reason more time is needed is when higher molecularweight polyesters (such as those greater than 10,000 average number mw)are the goal. With higher molecular weight polyesters, the reactionbecomes longer when the equivalents of hydroxyl and acid components arecloser to being equal.

While initially the reaction proceeds rapidly, once reactiontemperatures have been reached the reaction starts slowing down as thefree acids and hydroxyl groups become less concentrated in the mix. Asthe reaction slows additional steps and techniques are used to continuethe reaction and create larger and larger molecular weights. With verylarge molecular weights (those greater than 30,000 mw) most often thematerial is transferred from the original vessel to one where moresurface area, heat and/or agitation can be applied. Even largermolecular weights can be obtained by using additional processing stepssuch as solid state reactions or transesterification.

The following is an excerpt from Organic Chemistry by Morrison and Boyd,pages 679-680, second edition: “In the esterification of an acid, analcohol acts as a nucleophilic reagent; in hydrolysis of an ester, analcohol is displaced by a nucleophilic reagent. Knowing this, we are notsurprised to find that one alcohol is capable of displacing anotheralcohol from an ester. This alcoholysis (cleavage by an alcohol) of anester in called transesterification.” “Transesterification is anequilibrium reaction. To shift the equilibrium to the right, it isnecessary to use a large excess of the alcohol whose ester we wish tomake, or else to remove one of the products from the reaction mixture.The second approach is the better one when feasible, since in this waythe reaction can be driven to completion.”

When making condensation polyesters, transesterification can be used asan additional processing step to achieve higher molecular weights withalready condensed polymers or monomers. At higher temperatures theelimination of an alcohol and subsequent removal of it by vacuum willgreatly increase molecular weight. At some point the end group can beliberated and removed by heat and/or vacuum thus building molecularweight. To extend the molecular weight of preformed polymers,transesterification sometimes follows an initial esterification stepwhere the monomer mix, usually containing excess glycols, is firstreacted to a point where most of the free carboxylic groups are used up.Or transesterification can be used alone to create polymers where thecarboxylic groups have been pre-formed into esters with an easilyvolatilized alcohol, most commonly methanol. Thus both esterificationand transesterification can be used separately or together in theprocess of making polyesters.

Over the years, many processes have been developed for manufacturingpolyesters. In the 1940's it was discovered that polyester polymerscould be made having very desirable properties such as clarity and highimpact strength through the condensation of aromatic dicarboxylic acidswith glycols using high temperatures and long reaction times to achievehigher molecular weights. By far the most important synthetic polyestertoday is polyethylene terephthalate (PET). This polymer is one where themultifunctional carboxylic acid is a terephthalate or terephthalic acidand the multifunctional alcohol is ethylene glycol. PET is a crystallinepolymer that can be used for a variety of items such as film textile,fiber, beverage bottles, and other types of containers.

One method of making PET is to start with dimethyl terephthalate andtransesterify with ethylene glycol liberating methanol. As methanol isremoved from the process the molecular weight is driven up. Severaltransesterification catalysts have been used for this method. Due to theenvironmental problems associated with methanol, it has become morecommon to use terephthalic acid and ethylene glycol with a suitableesterification catalyst. Again there are a number of such catalystsused.

Esterification of terephthalic acid requires high temperatures, inexcess of 200° C., and long reaction times, sometimes longer than 24hours. Thus it becomes a very energy intensive polymer to make. Whenvery high molecular weights are needed, 50,000 or greater (which isconsidered low compared to other polymers), solid state reactors areused to vacuum as much glycol off as possible thus extending the chainlength through transesterification and the removal of glycol. Additionalheat and time are needed.

The PET manufacturing segment of the polymer industry has become solarge that the cost of the raw materials of the PET polymer is low incomparison to other similar performance polymers. Large PET processinglines dedicated entirely to the manufacture of the PET polymers producePET polymer on a continuous basis. Due to this production there has beena great deal of controversy over the large amounts of PET that are beingrecovered from post consumer waste streams. Due to this abundance ofpost consumer waste, there have been a large number of patents issuedthat concern the utilization of this PET waste. As we progress in themanufacturing techniques for other monomers and the need for higherperformance materials become greater we will naturally expect to see theutilization of other condensation polymers to the point where theybecome prevalent in the waste streams. This has already started tohappen with PET containing other barrier materials and with PEN orpolyethylene napthalate.

As the waste stream from recycling started producing waste PET inabundance there were several patents written to utilize this potentialraw material source. These patents became a technology in their ownright. The first approaches to using PET were geared toward breakingdown the ester linkages through hydrolysis with water or glycolysis.Glycolysis is a specific form of transesterification where excess glycolis used to degrade the molecular weight. In this way the individualcomponents of the PET can be regenerated. In U.S. Pat. No. 4,078,143issued to Malik, et al. entitled “Process for depolymerizing wasteethylene terephthalate polyester”, a process is described where PET isbroken down by glycolysis to bis-(2-hydroxy ethyl) terephthalate, amonomer that can be utilized to reform the PET. In U.S. Pat. No.4,163,860, issued to Delatte, et al. entitled “Process for obtainingdimethyl terephthalate from polyester scrap” methanol is used totransesterify scrap PET back to dimethyl terephthalate that is purifiedfor use in the PET manufacturing process. In U.S. Pat. No. 4,355,175,issued to Pasztaszeri entitled “Method for recovery to terephthalic acidfrom polyester scrap”, a method of hydrolyzing the PET and purifying andrecovering the terephthalic acid is described. In U.S. Pat. No.4,578,502 issued to Cudmore entitled “Polyethylene terephthalatesaponification process”, a process is described wherein PET is brokendown into its monomeric constituents through saponification with alkali.In U.S. Pat. No. 4,929,749 issued to Gupta, et al. entitled “Productionof terephthalate esters by degradative transesterification of scrap orvirgin terephthalate polyesters”, higher boiling alcohols are used totransesterify the PET into lower molecular weight materials for use asraw materials for the manufacture of other polymers. In U.S. Pat. No.5,101,064 issued to Dupont, et al. entitled “Production of terephthalateesters by degradative transesterification of scrap or virginterephthalate polyesters”, a process is described where groups having 6to 20 carbons are used to degrade the PET, distill off the glycolbyproduct, and recover the diester.

In U.S. Pat. No. 5,266,601 issued to Kyber, et al. entitled “Process forpreparing polybutylene terephthalate from PET scrap” a method of usingPET by glycolysis and ester exchange with 1,4 butanediol and subsequentpolycondensation is described. In U.S. Pat. No. 5,319,128 issued toDupont, et al. entitled “Production of terephthalate esters bydegradative transesterification of scrap or virgin terephthalatepolyesters” a method of tranesterifying PET using higher molecularweight alcohols with 6 to 20 carbons and then recovering the diesters ofterephthalate is described. In U.S. Pat. Nos. 6,031,128 and 6,075,163issued to Roh, et al. entitled “Process for manufacturing terephthalicacid”, a process is described for manufacturing terephthalic acid fromwaste PET whereby PET is hydrolyzed to disodium terephthalate and thenacid neutralized to recover the free terephthalic acid. In U.S. Pat. No.6,472,557 issued to Pell, Jr. et al. entitled “Process for recyclingpolyesters”, a process for depolymerizing PET to dimethylterephthalateand then hydrolyzing it to terephthalic acid for reuse is described.Although all of these processes work, they are all very energy intensiveways of recycling the PET and do not utilize the time and energy thathas already gone into making the PET polyester. More often theseprocesses end up costing as much or even more than the cost of themonomers they are trying to reclaim. This is in large part due to thelow cost of the beginning PET feed stocks and the refined methods forconverting to the starting monomers. Also the additional energy requiredto reclaim the monomers from recycled PET adds substantially to thecost.

In the techniques used below, it is not necessary to take the PETpolymer all the way to its monomeric constituents and thus at least partof the time and energy of conversion of the terephthalic acid andethylene glycol is conserved. However in all cases thetransesterification conversion is done to break down the PET linkagesand lower the molecular weight to much lower oligomeric forms prior tosubsequent reactions.

There also are a number of methods for the utilization of PET as a rawmaterial for the manufacture of other polymers where terephthalic acidand/or ethylene glycol can be integrated as one of the components. Onesuch area is in the use of PET to make polyols that in turn are used formaking urethane foams. In U.S. Pat. No. 4,439,549 issued to Brennanentitled “Novel aromatic polyester polyol mixtures made frompolyethylene terephthalate residues and alkylene oxides” a method ofreacting PET with glycol to degrade to an oligomeric polyol and thensubsequent reaction of the polyol with an isocyanate moiety to producerigid foam is described. In U.S. Pat. No. 4,469,824 issued to Gigsby,Jr., et al. entitled “Liquid terephthalic ester polyols andpolyisocyanate foams therefrom”, PET is digested with diethylene glycoland other glycols with some of the ethylene glycol and then removed toform a polyol that reacts with an isocyanate to form a polyisocyanatefoam. In U.S. Pat. No. 4,485,196 issued to Speranza entitled “Liquidphase polyols which are alkylene oxide adducts of terephthalic esters” atechnique of making polyols for further processing into urethane foamsis described. The polyol is further reacted by ethoxylation orpropoxylation to liquefy and inhibit crystallinity. It is then usefulfor further conversion into polyurethanes. In U.S. Pat. No. 5,948,828issued to Reck entitled “Technology development and consultancy”reclaimed PET is digested with diethylene glycol, insolubles areremoved, and ethylene glycol and free diethylene glycol are removed toachieve a final hydroxyl value for a polyol. In U.S. Pat. No. 6,573,304issued to Durant, et al. in June of 2003 entitled “Method for obtainingpolyols and polyol thus obtained” a process for transesterification withglycols and subsequent removal of free glycols stopping at a narrowmolecular weight is described. These methods utilize excess glycol andtransesterification to shift the equilibrium back to lower molecularweight entities that can be further processed.

Some techniques developed utilizing PET have at least partiallypreserved some of the ester moieties and therefore some of the time andenergy already used in making the PET. In U.S. Pat. No. 4,977,191 issuedto Salsman entitled “Water-soluble or water dispersible polyester sizingcompositions”, a process is described where other polymers are made byfirst degrading the PET into oligomers containing the terephthalatemoiety and second building back up the molecular weight using otheraromatic or aliphatic acids. In U.S. Pat. No. 5,726,277 issued toSalsman entitled “Adhesive compositions from phthalate polymers and thepreparation thereof” adhesive compositions are described that are madefrom PET that is digested or transesterified with glycols andoxyalkylated polyols, either ethoxylated or propoxylated. A similar typeof reaction is used in U.S. Pat. No. 5,958,601 issued to Salsmanentitled “Water dispersible/redispersible hydrophobic polyesters resinsand their application in coatings”. In this patent however an ester of afatty acid and alcohol containing free hydroxyl groups is used incombination with glycols to degrade the PET polymer to lower molecularweight species before a molecular weight buildup is done with additionalaromatic acids.

There are additional polymer applications where PET has been used as araw material as well. In U.S. Pat. No. 5,820,982 issued to Salsmanentitled “Sulfoaryl modified water-soluble or water-dispersible resinsfrom polyethylene terephthalate or terephthalates” compositions aredescribed which contain the terephthalate moieties along with sulfonatedaromatic groups. Such resins are useful for adhesives, ink resins, dyeleveling on polyester and nylon fibers, etc. The process for preparationof these compositions requires a PET glycolysis step followed byadditional acids and a molecular weight buildup esterification step. Theprocessing times can be 12 to 24 hours. In U.S. Pat. No. 6,133,329issued to Shieh, et al. entitled “Thermoplastic polyester resincomposition” a composition is described where PET is first digested witha glycol mixture for 3 hours at high temperatures and then reacted witha natural oil for making it compatible with hydrocarbon andhydrofluorocarbon blowing agents. In U.S. Pat. No. 6,512,046 issued toUeno, et al. entitled “Polymerizable unsaturated polyester resincomposition” several compositions are described where PET is firstdepolymerized to achieve a polyester skeleton, then built back up with adibasic acid, and further reacted with an unsaturated monomer. In U.S.Pat. No. 6,534,624 issued to Ito, et al. entitled “Process for producingalkyd resins” a process is described where polyester is depolymerizedand then esterified in a mixture of alcohols, glycols, fatty acids, etc.It is noted in this patent that the use of terephthalic acid has notbeen in practice in the past with alkyd technology because thiscomponent is more costly than phthalic or phthalic anhydride. Again allof these patents, some very recent, describe first a depolymerizationstep and then an esterification step to build back up molecular weightto make polymers suitable for other areas of use.

Other techniques deal with the use of reclaimed PET by cleaning up thePET from other wastes and using it as a co-blend prior to or in anextruder with virgin PET or other polymers that can be coextruded withthe PET. Once reheated PET loses intrinsic viscosity (I.V.). Intrinsicviscosity has become a much easier method of comparing molecular weightsof PET than other more time consuming methods. Once processed, theintrinsic viscosity drops and its use as a feedstock for the originalarticle made becomes limited. In U.S. Pat. No. 5,225,130 issued toDeiringer entitled “Process for reclaiming thermally strained polyesterscrap material” mixed streams of recycled PET are cleaned and postcondensed with virgin PET. In U.S. Pat. No. 5,503,790 issued to Clementsentitled “Method of producing disposable articles utilizing regrindpolyethylene terephthalate” recycled PET is used to create articles thatare less demanding of higher intrinsic viscosity. In U.S. Pat. No.5,554,657 issued to Brownscombe, et al. entitled “Process for recyclingmixed polymer containing polyethylene terephthalate” a process forrecovering PET that involves dissolving the PET from a recycled stream,removing the solvents, and rinsing the PET is described. In U.S. Pat.No. 6,399,695 issued to Moriwaki, et al. entitled “Thermoplasticpolyester resin composition” PET is melted with a polyolefin or glycidylmethacrylate to produce a composite material. In U.S. Pat. No. 6,583,217issued to Li, et al. entitled “Composite material composed of fly ashand waste polyethylene terephthalate” the PET is mixed with the entitledmaterials and extruded. In the above references no reaction of the PETtakes place even though there are subsequent reprocessing steps. Thereare many other references where recycled PET is cleaned and used as partof the mixture back into articles such bottles, film, etc. Limitationsdue to the lower intrinsic viscosity of the recycled PET reduce theamount used in critical applications to 5% or less.

There are also current practices where PET is modified bytransesterifying with polyethers. These can be glycols or alcohols thathave been ethoxylated or propoxylated. These polymers contain the blocksegments of PET with block segments of the polyethers and thus usuallyexhibit properties of both. In U.S. Pat. No. 4,785,060 issued to Naglerentitled “Soil release promoting PET-POET copolymer, method of producingsame and use thereof in detergent composition having soil releasepromoting property” PET and a polyoxyethylene polymer are reactedtogether in a reactor such that an equilibrium is reached. This reactionis based on transesterification of the hydroxyl end groups of thepolyether with the ester linkages contained in the PET. In U.S. Pat. No.6,454,982 issued to Branum entitled “Method of preparing polyethylenemodified polyester filaments” a method is described wherein polyethyleneglycol is reacted into PET under transesterification conditions andsolid stated to a higher intrinsic viscosity.

In the referenced documents, glycols, polyethers, or simple glycolmonoesters are used to degrade or lower the molecular weight of the PETin order to get to monomeric or oligomeric forms of terephthalic acidthat can be further utilized as a polyol source for urethanes, to use asadhesive components with glycidyl ethers to form epoxies, or as coatingsand/or adhesives.

Another polymer of commerce is polyethylene naphthalate PEN. Within thelast few years there has been much activity regarding the use of PETwith PEN polymers. This is due in part to better properties such asclarity, strength, and increased crystallinity that translates to betterbarrier properties obtained with PEN. However, PEN is much moreexpensive than PET. Therefore, several processes for making copolymersof the two have been developed. In U.S. Pat. No. 5,902,539 issued toSchmidt, et al. entitled “Process for making PEN/PET blends andtransparent articles therefrom” a process is described where ethyleneglycol is used to reduce the intrinsic viscosity and increase the rangeof use for PET and PEN copolymers.

The following is an excerpt from U.S. Pat. No. 6,414,063, issued toBassam, et al. entitled “Nucleated pet/pen polyester compositions.” “Itis known that medium content PET/PEN compositions (compositions withPET:PEN ratios around 50:50) are amorphous in nature. The range ofcompositions which display this amorphous behaviour is generallyaccepted to be around PET:PEN=20:80 to PET:PEN=80:20, as described bytwo PEN manufacturers—Shell (see FIG. 1 of presentation to “BevPak”conference, Spring 1995, U.S.A) and Hoechst-Trevira (page 4 ofPolyclear® N technical literature). The disadvantage of this behaviouris that the use temperature of compositions in the 80/20 to 20/80 regionis substantially reduced. The use temperature is dependent on the glasstransition temperature (Tg) in this region. In contrast, the usetemperature of PET/PEN compositions with <20% PET or <20% PEN isdependent on the crystalline melt temperature (Tm). Tm is over 100° C.higher than the Tg for PET/PEN compositions; hence resulting in thesubstantial reduction in use temperature observed in the 20/80 to 80/20composition region. The same observations on the amorphous/crystallinenature of PET/PEN compositions were also made by Lu and Windle (see FIG.2 in Polymer 36 (1995), pages 451 459) and Andresen and Zachmann(Colloid & Polymer Science 272 (1994), page 1352). Andresen and Zachmannalso found that blends of PET and PEN formed a single phase within 2minutes of melting. This is usually good evidence for rapid formation ofa PET/PEN copolyester by transesterification. Thus the behaviour ofPET/PEN blends and copolymers can be expected to be the same withregards to crystallisation during all melt processing operations. In thecase of bottle manufacture using PET/PEN copolymers and blends, U.S.Pat. No. 5,628,957 (to Continental PET Technologies Inc.) states thatmid-range PET/PEN compositions containing 20 to 80% PEN aresubstantially amorphous and describes the use of an additionalstrain-hardenable (ie. crystallisable) layer for these mid-range PET/PENbottles.”

It is especially interesting to note from this patent that the blendsformed a single phase within 2 minutes of melting. Presumably from thisand information presented in the description one can surmise that estercompatibility increases the rate of transesterification. Also, it can beinferred that PET and PEN copolymer combinations have been made viamelting and/or processing since combinations of the two polymers werestarted. Again transesterification of the two is the chemistry thatmakes this happen. In U.S. Pat. No. 6,586,558 issued to Schmidt, et al.entitled “Process for making PEN/PET blends and transparent articlestherefrom” glycols are used to lower the intrinsic viscosity and allowmore processable viscosities for blends of these two polymers. Againtransesterification allows this to occur.

While there has been a lot of activity directed toward utilizing PET asa raw material to manufacture other polymers or as a composite material,PET is not being utilized in these polymers as a raw material. Theproblems that exist with these prior techniques include raw materialcontamination, difficulty of reaction, and incompatibility with one ormore of the other reactive groups. For instance, in U.S. Pat. No.5,250,333 issued to McNeely, et al. entitled “Modified polyethyleneterephthalate” there is described compositions where other alkoxylatedpolyols and dicarboxylic acids are used in combination with terephthalicacid and ethylene glycol to produce a less crystalline form of PET.Indeed there are many applications that use terephthalate moieties butrequire less crystallinity than that of PET. For instance, there aremany film applications that require less crystallinity for moreelastomeric properties. The polyols mentioned in the previous paragraphsare another example. In U.S. Pat. No. 6,428,900 issued to Wang entitled“Sulfonated copolyester based water dispersible hot melt adhesive” apolyester which contains water dispersible sulfonated branchedcopolyester polymers is described. These copolyester polymers usedifunctional carboxylic acids like terephthalic acid in their makeup.Crystallinity would inhibit water redispersibility which is an importantaspect of the disclosure. In U.S. Pat. No. 6,555,623 issued to Yang, etal. entitled “Preparation of unsaturated polyesters” a process isdescribed where MPD (methyl propanediol) is used along with aromaticdiacids such as terephthalic acid and maleic anhydride to produceunsaturated polyesters suitable for further reaction through theunsaturated group. Again polymer crystallinity is to be avoided.

There are a number of polymers that currently utilize phthalic anhydrideas a preferred difunctional aromatic acid. One reason for this is thatfor practical considerations one of the acid groups has already beenreacted and is an anhydride. This lowers the weight percent needed inthe subsequent polymers being made. In addition phthalic anhydrideesterifies at lower temperatures than terephthalic acid. Usingterephthalic acid as an alternate would not be as economical to beginwith. But terephthalic acid could be used if the right process to userecycled PET were available that would eliminate this economicaldifference.

There are a number of polymers containing ester linkages and the numberand scope of polymers that utilize or could utilize the raw materialsthat make up PET or other condensation polymers of commerce are toonumerous to list within the scope of this write. The following broadbased articles of commerce all use or have used terephthalic acid (oraromatic acids like phthalic acid or anhydride) and/or ethylene glycolin their monomer makeup:

-   -   (1) Adhesives: either hot melt, water borne, or reactive;    -   (2) Ink resins: both as the binding agent and the carrier        vehicle;    -   (3) Unsaturated resins: alone or in combinations with reactive        diluents such as acrylics or styrene for composite mixtures with        fiberglass, carbon fiber, etc.;    -   (4) Alkyd resins: both long and short alkyds for coatings and        paint applications;    -   (5) Urethanes: As the polyol portion together with isocyanates        to form adhesives, structural resins, or foams;    -   (6) Films: Less crystalline films for shrink wrap, laminating,        etc.; and    -   (7) Polyols for powder coatings or fusable coatings.

As described above, PET (either virgin or recycled) is recognized as amaterial that can be used to make more PET, PET composites, or otherpolymers that contain terephthalate groups. The processes that have beenused to make these materials contain within their steps glycolysis (orhydrolysis) of the ester linkages to create the beginning monomers suchas terephthalic acid, or a much lower molecular weight terephthalateoligomer that can be reacted to generate more PET or other polymersthrough esterification. In no circumstance has there been activity thatindicates advantage taken of the high molecular weight of PET (polyesterpolymers) being used to build higher molecular weight, on the order of10,000 to 20,000, through transesterification with a lower molecularweight polyester.

In U.S. Pat. No. 7,157,139 issued to Salsman (January 2007) the issue ofpreservation of the high molecular weight of PET is addressed. The highmolecular weight in PET is used to build the molecular weight of a lowermolecular weight modifying polymer. The process described thereinpreferably involves two-steps that can be used to take full advantage ofthe high molecular weight of a precondensed polymer, like PET, toproduce a new high molecular weight polymer. The first step, whichinvolves no polymer of commerce, takes all the other monomers that areto be contained within the finished polymer, and reacts them firstthrough esterification to form a modifying polymer containing terminalhydroxyl groups. In the second step, a commercially availablecondensation polymer such as PET is transesterified with the modifyingpolymer using heat and agitation to form the finished polymer.

The description herein of certain advantages and disadvantages ofvarious features, embodiments, methods, and apparatus disclosed in otherpublications is not intended to limit the scope of the presentembodiments. Indeed, the preferred embodiments may include some or allof the features, embodiments, methods, and apparatus described abovewithout suffering from the same disadvantages.

SUMMARY OF THE EMBODIMENTS

It is a feature of an embodiment to provide a process for manufacturinga polyester polymer. Still another feature is to provide a process formanufacturing a polyester polymer from PET or other commerciallyavailable condensation polymers.

An additional feature of the embodiments is to provide a process formodifying PET or other commercially available condensation polymers. Yetanother feature is to provide a process for modifying PET or othercommercially available condensation polymers without degradation to formhigh molecular weight cross-linked polymers.

It is an additional feature of the embodiments to provide a process formodifying PET or other commercially available condensation polymers byutilizing a plurality of appropriate monomers. Still an additionalfeature is to provide a process for modifying PET or other commerciallyavailable condensation polymers by transesterifying the appropriatemonomer mix with the PET or other commercially available condensationpolymers.

In accordance with these and other related features, the embodimentsprovide a process for manufacturing a polyester polymer from PET orother commercially available condensation polymers. The process involvesselecting a beginning monomer mix from a plurality of appropriatemonomers and transesterifying with the PET or other commerciallyavailable condensation polymers to form a useful new polymer. Nopolyesterification is used in the process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The terminology used herein is for the purpose of describing particularembodiments only, and is not intended to limit the scope of the presentinvention. As used throughout this disclosure, the singular forms “a,”“an,” and “the” include plural reference unless the context clearlydictates otherwise. Thus, for example, a reference to “a carpet backing”includes a plurality of such carpet backings, as well as a single carpetbacking, and a reference to “an adhesive composition” is a reference toone or more adhesive compositions and equivalents thereof known to thoseskilled in the art, and so forth.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention pertains. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methods,devices, and materials are now described. All publications mentionedherein are cited for the purpose of describing and disclosing thevarious materials, compositions, and carpet manufacturing methods thatare reported in the publications and that might be used in connectionwith the invention. Nothing herein is to be construed as an admissionthat the embodiments described herein are not entitled to antedate suchdisclosures by virtue of prior invention.

Monomers in the process disclosed herein typically are molecules thathave molecular weights lower than 1,500 and contain one, two, or morethan two reactive hydroxyl or ester groups that can transesterify withesters. The phrase “modifying monomer mix” as it is used herein,includes a monomer or mixtures of monomers used to modify throughtransesterification a PET, PEN, or other high molecular weight polyesterof commerce (herein referred to as PET), to achieve a new polymer withnew desired properties.

The process described herein preferably entails a one step reaction usedto build up a new polymer using PET or other high molecular weightpolyesters. The one step can be accomplished in stages of PET adds to amodifying monomer mix that has characteristics that both dissolve andtransesterify the PET. Transesterification is a reaction that takesplace when an OH or alcohol group becomes a nucleophile and exchangestake place at an ester linkage. A polymer preferably is made containingthese groups as a combination of end groups and esterified linkages.While not intending on being bound by any theory of operation, theinventor believes that as PET is added, molecular weight builds as themonomers break into the PET and become oligomer chains containingfunctional groups. Subsequent PET is not only believed to be dissolvedfaster by an oligomer that now possesses terephthalate moieties, butproduces larger and larger molecular weight chains as more and more PETis added. Transesterification continuously occurs above the polymer's Tg(glass transition temperature) and the alcohol generated from thenucleophile displacement itself becomes a nucleophile that can furtherreact. In this way the reaction may continue until at some pointequilibrium is reached where no further change in the polymer mixtureoccurs as the number of new end groups formed is in equilibrium with theamount and type of new ester linkages formed and the mixture becomes ahomogeneous new polymer. If the modifying monomer mix contains largesegments in between reactive end groups, then the homogeneous newpolymer can take on characteristics more like the large segments. If themixture contains segments with end groups that participate more or lessequally in the transesterification process, then the new polymer becomesa homogeneous polymer with new properties relative to the startingmaterials.

One of the parameters the inventor believes important to control inpolymer synthesis is molecular weight. In the process disclosed herein,it is believed that multi-functional monomers containing more than tworeactive groups in the modifying monomer mix introduce sites thatprovide cross-link density. Cross-link density can be important inmaintaining molecular weight properties. The final molecular weight maybe controlled by the amount of monomers containing more than tworeactive groups in the modifying monomer mix and the percentage of thatmodifying monomer mix reacted with the PET. For instance, if PET is usedin quantities above 60 percent, a lower amount of multifunctionalmonomers containing more than two reactive groups are needed in themodifying monomer mix as PET supplies the linear molecular weight neededto make a polymer of sufficient molecular weight. Sufficient molecularweight depends upon the final properties desired and is usually highenough to achieve some tenacity and or film strength. Further processingof the new polymer, however, may be desirable.

With the manufacture of polyesters through condensation alone themolecular build up is rapid initially and slows down considerably as themolecular weight increases. The process described herein differssubstantially from other processes that utilize PET in that noesterification reaction is needed. The polymer process is basedcompletely on transesterification. This not only opens up the use of amuch broader range of reaction vessels, but also greatly reduces processtimes since in polymer synthesis transesterification is a much fasterreaction than polyesterification.

The process described in the embodiments eliminates many of the problemsassociated with the known processes described earlier. Known processesdigest PET to reconstitute the original starting materials, which inmany cases is more expensive than the cost of manufacturing the startingmaterials. Once digested, the materials have to be re-condensed, whichis inherently energy inefficient and produces toxic levels of glycol anddioxane in the waste stream. Thus, only small amounts of PET arereprocessed in this manner. In contrast, the process of the embodimentseliminates these problems since it preserves the ester linkages alreadyformed in the commercially available condensation polymer so thatre-condensation of monomers or oligomers is unnecessary. In this regard,it becomes easier to consider transesterification as the molecularweight building step for the lower molecular weight modifying monomermix. As PET is added, molecular weight builds, and depending on theamount of monomers containing more than two reactive groups, cross linkdensity increases. The reaction mass changes from monomeric, tooligomeric, and then to polymeric as more PET is added and the reactionproceeds.

The process of the embodiments preferably involves the rapidtransesterification of a PET polymer with a modifying monomer mix.Careful monitoring of temperatures and reaction rates are not necessarywith the only requirement being enough heat to transesterify the mixtureto an equilibrium state. Reaction rates are dependent on several factorsincluding (1) time, (2) temperature, (3) modifying monomer mix, (4)hydrophilicity of modifying monomer mix, (5) number and type of hydroxylfunctionality contained in the modifying monomer mix, and (6)transesterification catalyst. Of these factors, higher temperatures arebelieved to have the most effect on the time required to complete thereaction. For example, depending upon the catalyst, goodtransesterification of terephthalates starts around 200° C., greatlyaccelerates around 240° C., and is very rapid around 260 d° C. Reactiontime at 200° C. is about ten hours to transesterify PET with a glycollike diethylene glycol. Reaction rate is reduced to about one hour at240° C. and only fifteen minutes at 260° C. Heating is not assignificant an issue since water is not being produced to hinder theincrease in temperature. With more hydrophobic modifying monomers andmodifying monomers with secondary hydroxyl groups or esters, thesereaction times would be longer since the solubility of the PET is lower.Those skilled in the art will appreciate that the choice of thebeginning modifying monomer mix may reduce reaction time, becauseselecting those monomers that provide more rapid breakdown may be usefulto offset these longer reaction times.

In some instances, the process of the embodiments does not require thecondensers or condensation receivers that are required in typicalesterification vessels, and consequently, less expensive equipment canbe used. In fact it is possible to complete the reaction in an extruderset up for the needed dwell times and mixing required. If no condensateis removed, no venting or condensers are required. The final desiredpolymer can be synthesized without further esterification, a major timeconsuming step in high molecular weight polyester synthesis. Theembodiments disclosed herein therefore provide advantages such as lowerreaction times, lower waste streams, higher utilization of PET, andhigher finished molecular weights with less energy and time.

When utilizing the process described in the preferred embodiments, itmay be advantageous to eliminate some of the lower molecular weightglycols produced in equilibrium in the reaction. For example, in thecase of PET, it may be advantageous to remove some ethylene glycol as itis formed. In this way the properties imparted by the modifying monomermix can be amplified. Removal of some ethylene glycol also may shift theequilibrium to a higher molecular weight so less monomers containingmore than two reactive groups are needed for molecular weight gainthrough cross link density. This allows for the production of morelinear polymers. If a monomer is used that has ester end groups such asa methyl ester, then methanol is produced in the reaction and can beremoved to extend molecular weight.

The staged addition of the PET or condensation polymer may become morerelevant as the total level used in making new polymers is increasedabove about 40 percent. At this point, it may become difficult tomaintain the PET in a suspended state in a reactor, and problems canarise as the PET reaches its melting point and is more compatible withitself than with the modifying monomer mix. If the PET is added instages of increasing amounts to the modifying monomer mix, it ispossible to produce new polymers that contain more than 90 percent ofthe PET.

Staging the addition of the condensation polymer and allowing someequilibrium to be reached at each stage may reduce problems in anagitated reactor. The problems are much less pronounced if the processis performed within an extruder. However, other problems such asincompatibility between the PET and the modifying monomer mix can makeextruder reactions more difficult, when compared to an agitated reactor.

The process described herein enables production of a polymer in twoparts. First, a polymer can be made in a reactor using PET to buildproperties such as molecular weight. Then, additional PET can be addedin an extruder to create an even higher molecular weight polymer withproperties that only very high molecular weight polyester polymers canachieve.

One of the purposes for staging the addition of PET is in allowing eachaddition to react in before additional material is added. A secondarypurpose is to allow the temperatures to come back to a level where rapidtransesterification can occur. One can readily see that with the properequipment, the PET staging could be part of a continuous feed systemthat maintains the reaction conditions at optimum temperatures andoptimum amount of fresh PET, until the entire amount of PET needed hasbeen added.

This process can be used for generating polymers for a variety ofapplications. Lower molecular weight polymers, with subsequently lowermelting points, provide excellent adhesives. Hydroxyl-terminated resinsprepared in accordance with the embodiments described herein can be usedas polyols for further reaction with epoxies or isocyanates in urethaneproduction. Slightly higher molecular weight polymers prepared inaccordance with the embodiments can be used as coatings such as hot meltcoatings or powder coatings. Higher molecular weight polymers preparedin accordance with the embodiments also can be used as fibers. Furtheruses could involve augmentation of current film or fiber forming resins.Further processing of the polymers prepared in accordance with theembodiments with anhydrides could yield acid-terminated polymers forneutralization with bases and modified water dispersibility.

The preferred embodiments described herein relate to a method of makinga polymer using a commercially available condensation polyester as a rawmaterial that includes selecting a modifying monomer mix, andtransesterifying the modifying monomer mix with the commerciallyavailable condensation polyester at a quantity predetermined by an enduse application, to produce a final polymer. In accordance with theprocess, the modifying monomer mix includes at least one monomer, the atleast one monomer preferably being a molecule including a hydroxyl or anester, that is capable of participating in transesterificationreactions, and that has a molecular weight of less than 1500. Themodifying monomer mix preferably does not include components derivedfrom the commercially available condensation polyester.

Suitable commercially available condensation polyesters useful as a rawmaterial in the processes described herein include those capable oftransesterification with the modifying monomer mixture. Preferably, thecommercially available condensation polyesters are those selected fromPET, PBT, PEN, PTT (polytrimethylene terephthalate), and mostpreferably, these condensation polymers are recycled from existingmaterials containing these materials. The commercially availablecondensation polyesters typically are used in an amount ranging fromabout 30 to about 96 weight percent, based on the total weight of thepolymer produced, and preferably from about 60 to about 80 weightpercent. Skilled artisans are capable of selecting a suitablecommercially available condensation polyester for use in theembodiments, using the guidelines provided herein.

The modifying monomer mix useful in the processes described hereinpreferably include those with pendant hydroxyl or ester groups, andpreferably, although not necessarily, have a molecular weight of lessthan about 1500. The molecular weight can be calculated from thestructure from the monomer, or is already known from manuals (e.g.,trimethylol propane has a molecular weight of about 134). Preferably,the molecular weight of the monomer mix is less than about 1,300, andmore preferably less than about 1,200, wherein the molecular weight isthe total molecular weight of all of the monomers used in the mixture.

The monomer mix may include a single monomer, or a mixture of monomers.Suitable monomers include, but are not limited to alcohols, acids,polyethoxylates, ethoxylate condensates, esters, di-esters, tri-esters,and amines and amides with functional alcohol groups. Suitable alcoholsinclude, but are not limited to butanol, hexanol, lauryl alcohol,decanol, glycerine, trimethylolpropane, neopentyl glycol, ethyleneglycol, sorbitol, pentaerythritol, cyclohexane dimethanol, stearylalcohol, and the like. Suitable acids include, but are not limited toadipic, lauric, palmitic, stearic, oleic, behenic, linolenic, succinic,maleic, maleic anhydride, butanoic, phthalic, phthalic anhydride,isophthalic, terephthalic, trimellitic anhydride, and the like. Suitablepolyethoxylates include, but are not limited to diethylene glycol,triethylene glycol, polyethylene glycol 200, polyethylene glycol 400,polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol1000, and the like. Suitable ethoxylate condensates include, but are notlimited to 1 to 25 moles of ethylene oxide on the alcohols or acidslisted above. Suitable esters, di-esters, and tri-esters include, butare not limited to the acids and the (alcohols, polyethoxylates, orethoxylate condensates) above such as butyl laurate, ethylene glycoldistearate, cyclohexane dimethanol dioleate, etc. Suitable amines oramides with functional alcohol groups include, but are not limited toethylene oxide condensates of amines. It is preferred in the embodimentsthat the monomers used to formulate the monomer mix are not the samemonomers used to make the commercially available polyester with which itis reacted.

The amount of monomers used in the monomer mix typically will varydepending on the desired use of the resulting polymer. Those skilled inthe art will be capable of determining the amount of monomer mix usefulin the processes described, using the guidelines provided herein.

The time of reaction and temperature of reaction also may vary dependingon the monomer mix and commercially available polyester. Preferably, thereaction takes place at a temperature within the range of from about 150to about 350° C., preferably from about 200 to about 290° C., and for aperiod of from about 0.5 to about 10 minutes, preferably from about 1 toabout 5 minutes. The embodiments now will be described with reference tothe non-limiting examples.

EXAMPLES

The following examples, unless otherwise stated, were all prepared in a250 milliliter flask fitted with a condenser, a funnel for theintroduction of polymer adds, a thermometer, a variable speed agitator,a tube for the introduction of an inert gas, and a heating mantel with ascaled rheostat controller. The table in the examples represent theingredients, percentage of each, amount in grams charged, and number andquantity of staged adds in grams. The PET (polyethylene terephthalate)used was repelletized PET obtained from the recycling of PET beveragebottles. The PEN (polyethylene naphthalate) was pelletized, virginmaterial.

Example 1

Staged Amount Adds of Ingredients Percent Charged PET Bis-diethyleneglycol adipate 25.00 50.00 Tyzor TPT 0.01 0.02 PET in pellet form,crystallized 74.99 149.98 1-25 2-15 3-15 4-20 5-25 6-25   7-24.98 Total100.00 200.00 149.98

The bis-diethylene glycol adipate and the Tyzor TPT were added to theflask and heated to 200° C. with agitation. The PET was then added instages. After each add the temperature was brought to 250° C. withagitation and allowed to become fully homogeneous and clear before thenext staged add. The final polymer was held at 250° C. for an additional30 minutes before cooling. Total time for this reaction was 2 hours and10 minutes. The polymer's properties improved with each add of PET.Although still somewhat tacky the polymer exhibited decreasedcrystallinity at room temperature. There was not enough room in theflask for more PET adds, but it was evident that higher molecularweights could be obtained with increasingly levels of PET.

Example 2

Amount Staged Adds Ingredients Percent Charged of PET Bis-diethyleneglycol adipate 15.00 30.00 Tyzor TPT 0.01 0.02 PET in pellet form,crystallized 84.99 169.98 1-15 2-15 3-20 4-20 5-25 6-25 7-30   8-19.98Total 100.00 200.00 169.98

The bis-diethylene glycol adipate and the Tyzor TPT were added to theflask and heated to 200° C. with agitation. The PET was then added instages. After each add the temperature was brought to 250° C. withagitation and allowed to become fully homogeneous and clear before thenext staged add. The polymer was held an 30 minutes at 250° C. after alladds. Total time for this reaction was 2 hours and 30 minutes. Thepolymer produced had much higher strength properties relative toExample 1. PET having higher molecular weight is building up the newpolymers molecular weight with increasing levels. This resin appeared tobe a suitable candidate for a hot melt adhesive.

Example 3

Amount Staged Adds Ingredients Percent Charged of PET Bis-diethyleneglycol isophthlate 25.20 50.40 Tyzor TPT 0.01 0.02 PET in pellet form,crystallized 74.79 149.58 1-15 2-20 3-20 4-25 5-25 6-30   7-14.58 Total100.00 200.00 149.58

The bis-diethylene glycol isophthalate and the Tyzor TPT were added tothe flask and heated to 200° C. with agitation. The PET was then addedin stages. After each add the temperature was brought to 250° C. withagitation and allowed to become fully homogeneous and clear before thenext staged add. The polymer was held an additional 30 minutes at 250°C. after the last PET add. Total time for this reaction was 2 hours and40 minutes. The polymer produced had the appearance of a morenon-crystalline PET polymer, with a clear appearance even after slowlycooling. At this level of linear monomer the strength properties weremuch more like a hot melt resin than PET. The Isophthalic moiety (aknown decrystallizer for PET) was reacting in completely and wasbelieved to assist in decrystallizing the highly crystalline PET chains.

Example 4

Amount Staged Adds Ingredients Percent Charged of PET Bis-diethyleneglycol isophthalate 18.42 36.84 Ethoxylate Glycerine 11.46 22.92 TyzorTPT 0.01 0.02 PET in pellet form, crystallized 70.11 140.22 1-15 2-153-20 3-20 4-25 5-25   6-20.22 Total 100.00 200.00 140.22

The bis-diethylene glycol isophthalate, the ethoxylated glycerine, andthe Tyzor TPT were added to the reaction vessel and heated to 200° C.Ethoxylated glycerine was used because glycerine alone did not producesatisfactory results using similar conditions, although glycerine alonemay be satisfactory under other operating conditions. The PET was addedin stages with each stage brought up and back up to 250 C. After all thePET was added the polymer was kept at 250° C. for an additional 30minutes to insure equilibrium and homogeneity of the polymer. Thisreaction proceeded without problems. The polymer had an initialviscosity after finishing of 4 poise at 175° C. The polymer produced wasnot believed to be suitable for a coating polymer because the strengthwas too low, but the resulting polymer had properties that were suitablefor other polymer applications.

Example 5

A vacuum of 20 In. Hg was exerted on the polymer of Example 4 for 12minutes at 250° C. The viscosity went to 9 poise at 175° C. Theviscosity of this polymer was 9 poises at 175° C. The strength was goodand better than Example 4 but the polymer did not have adequateresilience for use as a coating polymer. The resulting polymer would besuitable for other polymer applications.

Example 6

Amount Staged Adds Ingredients Percent Charged of PET Bis-diethyleneglycol isophthalate 11.42 36.84 Glycerine-25 11.46 22.92 Trimethylolpropane 7.00 14.00 Tyzor TPT 0.01 0.02 PET in pellet form, crystallized70.11 140.22 1-15 2-15 3-20 4-20 5-25 6-25   7-20.22 Total 100.00 200.00140.22

The bis-diethylene glycol isophthalate, the glycerine-25, thetrimethylol propane, and the Tyzor TPT were added to the reaction flaskand the temperature was brought up to 200° C. as rapidly as possible.After the first staged add of PET and each subsequent add thetemperature was brought up to 250° C. rapidly with the rheostat set on80% after a clear, homogeneous reaction mass was achieved. Afterbringing up the temperature on the last add to 250° C. it was held for10 minutes and then a 20 minute vacuum at 250° C. was completed beforecooling.

This reaction was much faster than previous ones. The trimethylolpropane appeared to transesterify easily with the PET, and to act as abetter solvent in the initial stages. After all adds were completed, theinitial viscosity was 3 poise at 175° C. and after a vacuum of 20minutes at 250° C. it was 7 poise at 175° C. This material seemed to beless crystalline which points to either molecular weight or cross-linkdensity helping to prevent crystallization.

Example 7

Staged Amount Adds of Ingredients Percent Charged PET Cyclohexanedimethanol 12.50 27.50 Ethoxylated glycerine 12.50 27.50 Tyzor TPT 0.010.02 PET in pellet form, crystallized 74.99 164.98 1-15 2-15 3-20 4-205-25 6-30   7-39.98 Total 100.00 220.00 164.98

The cyclohexane dimethanol, the ethoxylated glycerine, and the Tyzor TPTwere added to the reaction vessel and heated to 200° C. The PET wasadded in stages with each stage brought up to 250° C. and allowed tobecome homogeneous and clear before the next stage. After all the PETwas added the polymer was kept at 250° C. for an additional 1 hour toinsure equilibrium and homogeneity of the polymer.

This reaction proceeded without problems. The polymer had an initialviscosity of 3 poise at 175° C. The cyclohexane dimethanol, a knowndecrystallizer for PET, was added to lower the crystallinity.Surprisingly, the addition did not appear to lower the crystallizationtemperature, and did not appear to lower the isophthalates andcross-link density, when compared to the polymer produced in accordancewith Example 4. This material was easy to grind into a powder and fuseagain with temperature. A possible advantage with the higher crystallinematerial would be to produce a fusible coating or thermoforming polymersor compositions that could be used alone or in combination with otherreactive or protective ingredients to provide a coating or thermoformingcomposition that had lower glass transition temperatures but was still apowder at room temperatures. This formula would be useful as a compoundfor fusible coatings or thermoforming applications.

Example 8

Amount Staged Adds Ingredients Percent Charged of PET Polypropyleneglycol 18.75 41.25 Trimethylolpropane 6.24 13.73 Tyzor TPT 0.01 0.02 PETin pellet form, crystallized 75.00 165.00 1-15 2-15 3-20 4-25 5-25 Total100.00 220.00 100.00

The polypropylene glycol (M.W. 1000), the trimethylol propane, and theTyzor TPT were added to the reaction flask and the temperature wasbrought up to 200° C. as rapidly as possible. After the first staged addof PET and each subsequent add the temperature was brought up to 250° C.rapidly with the rheostat set on 80% after a homogeneous reaction masswas achieved from the previous add. After only 100 grams of PET had beenadded the viscosity of the polymer seemed to be growing too rapidly.

This reaction was different in that a clear phase after the PET adds wasnever achieved. The polypropylene glycol may have had some solubilityproblems, which may have had an effect on the reactivity of thesecondary hydroxyl group. The reaction resulted in the synthesis of agelled polymer suspended in the polypropylene glycol. Once the materialwas removed from the flask the gelled polymer separated from thepolypropylene glycol. This polymer, composed of trimethylolpropane andPET, was strong, resilient, rubber-like and non-crystalline. Theviscosity was greater than 100 Poise at 200° C. The cross-link densitywas so high that the molecular weight was essentially approachinginfinity rapidly, and the presence of the polypropylene glycol as aseparate phase was beneficial.

Hot melt adhesive are polymers that have good adhesion usually to avariety of substrates. They have relatively low melting point and set upquickly to resilient but strong polymers.

Example 9

Amount Staged Adds Ingredients Percent Charged of PET EthoxylatedGlycerine 18.75 41.25 Trimethylolpropane 6.24 13.73 Tyzor TPT 0.01 0.02PET in pellet form, crystallized 75.00 165.00 1-25 2-25 3-25 4-25 5-256-25 7-15 Total 100.00 220.00 165.00

The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPTwere added to the reaction flask and the temperature was brought up to200° C. as rapidly as possible. After the first staged add of PET andeach subsequent add the temperature was brought up to 250° C. rapidlywith the rheostat set on 80% after a homogeneous and clear reaction masswas achieved from the previous add. The reaction mass was held at 250°C. for an additional 30 minutes after the last add was clear andhomogeneous. All of the PET was added without difficulties.

This reaction was far better than using polypropylene glycol orglycerine in that the extra ethylene oxide on the glycerine not onlyproduced easily accessable primary hydroxyls, but also seemed as more ofa solvent for the PET. Clear phases at each add were easy to achieve.The viscosity after the final PET had been added was 6 Poises at 175° C.but went to 10 Poise after a 30 minute hold. This material had improvedproperties of resiliency, tenacity, adhesion to a variety of substrates,and a relatively low melting point. The resulting polymer would providea good hot melt adhesive or in other adhesive applications.

Example 10

Amount Staged Adds Ingredients Percent Charged of PET EthoxylatedGlycerine 16.84 41.25 Trimethylolpropane 5.60 13.73 Tyzor TPT 0.01 0.02PET in pellet form, crystallized 77.55 190.00 1-25 2-25 3-25 4-25 5-256-25 7-15 8-25 Total 100.00 245.00 190.00

The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPTwere added to the reaction flask and the temperature was brought up to200° C. as rapidly as possible. After the first staged add of PET andeach subsequent add the temperature was brought up to 250° C. rapidlywith the rheostat set on 80% after a homogeneous and clear reaction masswas achieved from the previous add. The reaction mass was held at 250°C. for an additional 30 minutes after the last add was clear andhomogeneous. All of the PET was added without difficulties.

This reaction was similar to Example 8 only in that a larger percentageof PET was used. All conditions were the same and after the last add hadreached 250° C., and cleared the reaction mass was held for anadditional 30 minutes. The polymer had a viscosity of 13 Poise at 175°C. and was even stronger in properties to Example 8. The polymer had atendency to crystallize if cooled too slowly.

Example 11

Staged Adds of Ingredients Percent Amount Charged PET Polyethyleneglycol, 400 M.W. 70.00 154.00 Tyzor TPT 0.05 0.11 PET in pellet form,crystallized 29.95 65.89 1-30   2-35.89 Total 100.00 220.00 65.89

The polyethylene glycol with a molecular weight of 400 and the Tyzor TPTwere added to the reaction flask and the temperature was brought up to200 C. as rapidly as possible. After the first staged add of PET andeach subsequent add the temperature was brought up to 250° C. rapidlywith the rheostat set on 80% after a homogeneous and clear reaction masswas achieved from the previous add. The reaction mass was held at 250°C. for an additional 30 minutes after the last add was clear andhomogeneous.

This reaction was run mainly to see if enough of the PET had broken downto provide water solubility. With this much ethylene oxide-containingmaterial, water dispersibility should be achieved if the reaction iscomplete. The material dispersed in water easily and stayed clear formore than an hour. Since the hydroxyl value would be high on thispolymer and it remained in a liquid state, it would make an excellentpolyol for further reactions.

Example 12

The reaction product of Example 10 was further processed. The initialviscosity was low, 1 Poise at 175° C., so a vacuum was set up and theproduct was held for 1 hour total at 250° C. and with a 20 mm Hg vacuum.Samples were taken every 20 minutes. The initial viscosity became 3Poise at 175° C. after 20 minutes of vacuum, 8 Poises after another 20minutes, and 17 Poises after the final 20 minutes. The removal of theethylene glycol as it was formed created larger molecular weights, andit is conceivable that vacuum could continue to be applied until themolecular weight was quite high.

Example 13

Amount Staged Adds of Ingredients Percent Charged PET PEG 400 36.3572.70 20 + Alcohol 9.06 18.12 Tyzor TPT 0.01 0.02 PET in pellet form,crystallized 54.58 109.16 1-40 2-40   3-29.16 Total 100.00 200.00 109.16

The PEG 400, 20+Alcohol (a 20 carbon linear chain alcohol), and theTyzor TPT were added to the reaction flask and the temperature wasbrought up to 200° C. as rapidly as possible. After the first staged addof PET and each subsequent add the temperature was brought up to 250° C.rapidly with the rheostat set on 80% after a homogeneous but slightlyless than clear reaction mass was achieved from the previous add. Thereaction mass was held at 250° C. for an additional 30 minutes after thelast add was clear and homogeneous. The PET seemed to dissolve and reactwithout difficulties.

The 20+Alcohol was added to assess whether some chain termination with alonger chain aliphatic group would render the polymer less tacky at roomtemperature. This apparently worked quite well however upon standingsome of the less massive unreacted 20+Alcohol migrated to the surface.Although some reacted in apparently not all of the 20+alcohol reacted.This migration to the surface could be useful in some applications andnot desirable I in others. The polymer appeared to exhibit excellentadhesion when poured hot onto a substrate, and consequently, would makea good hot melt adhesive candidate.

Example 14

Staged Amount Adds of Ingredients Percent Charged PET PEG 400 25.0050.00 Ethoxylated Stearyl Alcohol 5.00 10.00 Tyzor TPT 0.01 0.02 PET inpellet form, crystallized 69.99 139.98 1-20 2-20 3-25 4-25 5-30  6-19.96 Total 100.00 200.00 139.96

The PEG 400, ethoxylated stearyl alcohol, and the Tyzor TPT were addedto the reaction flask and the temperature was brought up to 200° C. asrapidly as possible. After the first staged add of PET and eachsubsequent add the temperature was brought up to 250° C. rapidly withthe rheostat set on 80% after a homogeneous and clear reaction mass wasachieved from the previous add. The reaction mass was held at 250° C.for an additional 30 minutes after the last add was clear andhomogeneous. The PET seemed to dissolve and react without difficulties.

The ethoxylated stearyl alcohol was added to assess whether sometermination with a longer chain aliphatic group would render the polymerless tacky at room temperature. An ethoxylated C-18 alcohol was selectedto determine whether the ethoxylate group would add reactivity andsolubility to the reaction over the unmodified alcohol of Example 12.The results of a clear melt and no apparent blooming of unreactedmaterial to the surface confirmed that the ethoxylated stearyl alcoholadded reactivity and solubility to the reaction. The polymer appeared tohave improved adhesion when poured hot onto a substrate, butcrystallized too rapidly and may not have been strong enough for somecoating applications. The viscosity was 2 Poise at 175° C.

Example 15

Amount Staged Adds Ingredients Percent Charged of PET PEG 400 20.0040.00 Ethoxylated Stearyl Alcohol 5.00 10.00 Trimethyolpropane 5.0010.00 Tyzor TPT 0.01 0.02 PET in pellet form, crystallized 69.99 139.981-20 2-20 3-25 4-25 5-30   6-19.96 Total 100.00 200.00 139.96

The PEG 400, ethoxylated stearyl alcohol, trimethyolpropane, and theTyzor TPT were added to the reaction flask and the temperature wasbrought up to 200° C. as rapidly as possible. After the first staged addof PET and each subsequent add the temperature was brought up to 250° C.rapidly with the rheostat set on 80% after a homogeneous and clearreaction mass was achieved from the previous add. The reaction mass washeld at 250° C. for an additional 30 minutes after the last add wasclear and homogeneous. The PET seemed to dissolve and react withoutdifficulties.

Adding the trimethylolpropane to the polymer of Example 13 improved thestrength and resilience of the polymer. The polymer appeared to exhibitexcellent adhesion when poured hot onto a substrate and was approachinggood film strength. Upon setting some crystallization occurred. Theviscosity was 5 Poise at 175° C.

Example 16

Amount Staged Adds Ingredients Percent Charged of PET EthoxylatedGlycerine 21.25 46.75 Ethoxylated Stearyl Alcohol 2.30 5.06Trimethylolpropane 7.17 15.77 Tyzor TPT 0.01 0.02 PET in pellet form,crystallized 69.27 152.40 1-20 2-20 3-25 4-25 5-30   6-32.4 Total 100.00220.00 152.40

The ethoxylated glycerine, ethoxylated stearyl alcohol,trimethylolpropane, and the Tyzor TPT were added to the reaction flaskand the temperature was brought up to 200° C. as rapidly as possible.After the first staged add of PET and each subsequent add thetemperature was brought up to 250° C. rapidly with the rheostat set on80% after a homogeneous and clear reaction mass was achieved from theprevious add. The reaction mass was held at 250° C. for an additional 30minutes after the last add was clear and homogeneous. A vacuum waspulled for 10 minutes. The PET seemed to dissolve and react withoutdifficulties.

The ethoxylated glycerine was added to provide additional branched sitesfor strength characteristics through the increase of cross-link density,when compared with the polymer prepared in accordance with Example 14.The results showed that this addition did provide a slight boost inviscosity to 5 Poise at 175° C. The viscosity increase is believed to beattributable to an increase in molecular weight. The polymer was toughand resilient and slightly less crystalline than the polymer prepared inaccordance with Example 14. A 10-minute vacuum of 20 in Hg was appliedat 250° C. and the viscosity was 12 Poise at 175° C. Compounds were madeusing this polymer that proved to be suitable for hot melt coatingapplications.

Example 17

Staged Adds of Ingredients Percent Amount Charged PET Polyethyleneglycol, 400 M.W. 70.00 154.00 PET in pellet form, crystallized 30.0066.00 1-30 2-36 Total 100.00 220.00 66.00

The reaction of Example 11 was repeated using no Tyzor TPT to catalyzewith. The polyethylene glycol with a molecular weight of 400 was addedto the reaction flask and the temperature was brought up to 200° C. asrapidly as possible. After the first staged add of PET and eachsubsequent add the temperature was brought up to 270° C. rapidly withthe rheostat set on 80% after a homogeneous and clear reaction mass wasachieved from the previous add. The reaction mass was held at 270° C.for an additional 30 minutes after the last add was clear andhomogeneous.

This Example was conducted to assess whether the PET would transesterifywithout a catalyst. The PET appeared to add in slower, and consequently,the temperature was increased 20° C., which appeared to somewhat offsetthe absence of catalyst. Transesterification will occur with some formsof PET even without additional catalyst.

Sizing Compositions—film forming polymers that can be dispersed ordissolved in water are widely used for sizing textile fibers and paperproducts. These polymers in many instances have to retain theirsolubility because they are later removed.

Example 18

Amount Staged Adds Ingredients Percent Charged of PET Bis-diethyleneglycol sulfo- 11.50 23.00 isophthalate, sodium salt Glycerine ethoxylate9.00 18.00 Trimethyolpropane 4.50 9.00 Tyzor TPT 0.01 0.02 PET in pelletform, crystallized 74.99 149.98 1-10 2-15 3-20 4-20 5-25 6-25 7-25  8-9.98 Total 100.00 200.00 149.98

The bis-diethylene glycol sulfo-isophthalate (sodium salt), theglycerine ethoxylate, the trimethylolpropane, and the Tyzor TPT wereadded to the reaction vessel and heated to 200° C. The PET was added instages with each stage brought up to 250° C. before the next stage.After all the PET was added the polymer was kept at 250° C. for anadditional 1 hour to insure equilibrium and homogeneity of the polymer.

This reaction proceeded without problems. The polymer had an initialviscosity of 3 poise at 175° C. A vacuum of 20 in Hg was applied for 10minutes and the polymer's viscosity went to 12 Poise at 175° C. Thisresin dispersed easily in hot water. The bis-diethylene glycolsulfosiophthalate, sodium salt, was added to provide a water-solublegroup to the polymer. This polymer would make a suitable candidate forsizing compositions, ink jet resins, and any film-forming compositionsthat require water dispersibility.

Higher molecular weight fiber or film—In the production of fibers orfilms, the viscosity, resiliency, or other properties of the moltenresin should be high enough to allow further processing with the moltenmaterial. With many films, a certain degree of cross-link density isincorporated into the polymer to achieve this. It becomes necessary attimes to approach the gellation point of the polymer in order to achievethese running properties. With the process of the preferred embodiments,one skilled in the art can approach the gellation point by selecting anappropriate cross-link density in the modifying monomer mix, therebyachieving unheard of properties with great accuracy. In fact, in manycases gellation is a desirable property to achieve high strengths andcohesive properties. With this process, and the proper choice ofbeginning multifunctional alcohols or esters, gellation can beapproached with large quantities of the commercially availablecondensation polymer.

Example 19

Amount Staged Adds of Ingredients Percent Charged PET PEG 400 5.52 11.04Ethoxylated Stearyl Alcohol 0.60 1.20 Trimethylolpropane 1.86 3.72 TyzorTPT 0.01 0.02 PET in pellet form, crystallized 92.01 184.02 1-5  2-6 3-8  4-10 5-15 6-20 7-20 8-25 9-25 10-25    11-25.02 Total 100.00 200.00184.02

The PEG 400, ethoxylated stearyl alcohol, trimethylolpropane, and theTyzor TPT were added to the reaction flask and the temperature wasbrought up to 200° C. as rapidly as possible. After the first staged addof PET and each subsequent add through add 7 the temperature was broughtup to 250° C. rapidly with the rheostat set on 80% after a homogeneousand clear reaction mass was achieved from the previous add. Prior to add8 the temperature of the reaction mass was raised to 270° C. to offsetthe increase in viscosity. After add 8 the reaction was returned to 270°C. After Add 9 the reaction mass was brought up to 290° C. and againback to 290° C. after add 10 and 11. The reaction mass was held at 250°C. for an additional 1 hour after the last add was clear andhomogeneous.

It was difficult to stir such a small amount of modifying monomer mixwith any amount of PET. A kettle designed to agitate small amountsbetter initially would be preferred. Therefore, the reactor utilized inthis example required small initial adds and careful attention. No morePET was added because of the obvious viscosity increase that occurredwith the last add of PET. The final polymer had a melt viscosity ofgreater than 100 Poise at 200° C. but was still movable at highertemperatures. One could easily draw out a fiber from the molten mass andcontinue to draw indefinitely. This was a good film and fiber formingpolymer.

Polyols—The process described herein also can be used for making avariety of polyols. A polyol is generally a lower molecular weightmaterial containing terminating hydroxyl groups that can take part inother reactions to form higher molecular weight materials. A common usefor these polyols is in making polyurethane. Polyurethane is a rigid,semi-rigid, or flexible polymer that can be used to make a number ofmaterials such as adhesives, insulating foam, foam structural items likeshoe insoles, rubber-like structural items, and rigid structural items.

Example 20

Ingredients Percent Amount mixed Polyol of Example 17 48.79 20.03Polymethylene 49.65 20.38 polyphenylpolyisocyanate Water 1.51 0.62Di-butyl tin laurate 0.05 0.02 Total 100.00 41.05

The polyol of Example 17 was further reacted according to the formulaabove to produce a polyurethane foam. All the ingredients were mixed ina cup. The polymethylene polyphenylpolyisocyanate was added last toensure good mixing. After a few minutes the reaction started andproduced a volume of foam. Once cooled the foam was rigid, tough, andsuitable for some structural foam applications.

Example 21

Ingredients Percent Amount mixed Polyol of Example 4 79.88 16.83Polymethylene 20.07 4.23 polyphenylpolyisocyanate Di-butyl tin laurate0.05 0.01 Total 100.00 21.07

The polyol of Example 4 was further reacted according to the formulaabove to produce a polyurethane. All the ingredients were mixed in abeaker after heating the polymer to 130° C. The polymethylenepolyphenylpolyisocyanate was added last to ensure good mixing and mixedas rapidly as possible.

The reaction was quite rapid and vigorous stirring was conducted toobtain an adequate mixture of the components before the reactionstarted. Significant heat was produced. Once cooled, the polymer wasextremely tough and would be suitable for some molding applications.This is about the maximum molecular weight polymer that could be mixedby hand. It would be easy to produce an article with even less of thepolymethylene polyphenylpolyisocyanate and a higher molecular weightpolymer if the mixing was carried out in an extruder.

Film forming, acid-terminated, water-dispersible compositions or powdercoatings:

Example 22

The polymer from Example 14 was further processed by melting and pouringback into the reaction flask. Heating was continued until the polymerwas 180 degrees C. An additional 10% of trimellitic anhydride was addedto the 176.9 g. mass to get a final weight of 196.6 grams. The reactionmass was brought back to 180° C. and held for 1 hour.

The polymer produced from this further processing was higher inmolecular weight and had a finished viscosity of 15 Poise at 175° C. Ithad a relatively high Tg and was easy to grind into a powder that couldbe refused with heat. The powder also dispersed into 70° C. hot watercontaining 1% ammonium hydroxide to make a 20% dispersion suitable as awater dispersible coating composition. This polymer would make asuitable candidate for sizing compositions, ink jet resins, and anyfilm-forming compositions that require water dispersibility. Due to itsrelatively high glass transition temperature it also would make a goodcandidate for an acid-terminated powder coating.

Film Compositions from Polyethylene Naphthalate (PEN)—PEN is arelatively new polymer. Prior to the construction of a manufacturingsite by Amoco specifically for the manufacture of NDC, ordimethyl-2,6-naphthalenedicarboxylate the intermediate for PEN, the costof PEN was prohibitive for all but the most demanding applications.Today, however, many items of commerce utilize PEN.

There are advantages of using PEN over PET for packaging of certainarticles. For example, the barrier properties of PET are not believed tobe adequate for certain applications where barrier properties aredesirable. PET has been used for bottling beer, but because of the highpermeability of oxygen, it sometimes causes the flavor to deterioraterapidly. There have been several products where PET is laminated with ahigh oxygen barrier film to try to compensate for this. PEN has theneeded barrier properties. This and the fact that it can take highertemperatures that are used to pasteurize some liquids, it is expectedthat the use of PEN will increase over the next decade.

The process of the embodiments described herein can make use of PEN asthe commercially available condensation polymer. The temperaturesusually required to use this process with PEN are greater than that ofPET, and typically are on the order of 250 to 280° C.

Example 23

Amount Staged Adds Ingredients Percent Charged of PET PEG 400 20.0040.00 Trimethylolpropane 5.00 10.00 Tyzor TPT 0.01 0.02 PEN in pelletform, crystallized 74.99 149.98 1-10 2-10 3-20 4-20 5-25 6-25 7-30  8-9.98 Total 100.00 200.00 149.98

The PEG 400, trimethylolpropane, and the Tyzor TPT were added to thereaction flask and the temperature was brought up to 200° C. as rapidlyas possible. After the first staged add of PEN the temperature wasbrought to 260° C. and produced some amount of foam due to boiling ofthe monomer mix. This subsided and with each subsequent add through add8 the temperature was brought up to 265° C. rapidly with the rheostatset on 80% after a homogeneous and clear reaction mass was achieved fromthe previous add. After add 8 the reaction was returned to 280° C. andheld for 1 hour. This material seemed to behave similar to PET butrequired higher temperatures for transesterification to occur rapidly.The finished polymer was flexible and a good film forming material.

In the following examples, the process disclosed herein was performed ina small reactor suitable for making enough material to compound and runonto carpet.

Example 24

Amount Staged Adds Ingredients Percent Charged of PET EthoxylatedGlycerine 16.86 26.30 Pounds Trimethylolpropane 5.58 8.70 Pounds TyzorTPT 0.01 7.0 grams PET in pellet form, 77.55 121.00 Pounds 1-6 lbscrystallized 2-8 lbs 3-9 lbs 4-10 lbs 5-12 lbs 6-15 lbs 7-18 lbs 8-21lbs 9-22 lbs Total 100.00 156 Pounds 121 Pounds

The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPTwere added to the reactor and the temperature was brought up to 430° F.as rapidly as possible. After the first staged add of PET thetemperature was brought up to 450° F., after the 2nd and 3rd add up to460° F., after the 4^(th) and 5^(th) add up to 470° F., after the 6^(th)add up to 475° F., after the 7^(th) and 8^(th) add up to 480 F., andafter the 9^(th) and final add back up to 490° to 500° F. for 1 hour.All of the PET was added without difficulties.

The reaction went very similar to the lab reactions. The hot meltpolymer produced was further compounded into a backing material suitablefor carpet backing. The material was run and the carpet samples weretested and found to be suitable for commercial applications.

Example 25

Amount Staged Adds Ingredients Percent Charged of PET EthoxylatedGlycerine 18.00 24.8 Pounds Trimethylolpropane 4.87 6.7 PoundsEthoxylated Stearyl 3.49 4.8 Pounds Alcohol Tyzor TPT 0.01 7.0 grams PETin pellet form, 73.63 101.4 Pounds 1-6 lbs crystallized 2-8 lbs 3-9 lbs4-10 lbs 5-12 lbs 6-15 lbs 7-18.4 lbs 8-23 lbs Total 100.00 137.7 Pounds101.4 Pounds

The ethoxylated glycerine, trimethylol propane, ethoxylated stearylalcohol, and the Tyzor TPT were added to the reactor and the temperaturewas brought up to 430° F. as rapidly as possible. After the first stagedadd of PET the temperature was brought up to 450° F., after the 2nd and3rd add up to 460° F., after the 4^(th) and 5^(th) add up to 470° F.,after the 6^(th) add up to 475° F., after the 7^(th) add up to 480° F.and after the 8^(th) and final add back up to 490° to 500° F. for 1hour. All of the PET was added without difficulties and produced aclear, homogeneous melt.

The hot melt polymer made from this example was further processed into acompound and applied to the back of carpet. The finished product wasideal for a carpet backing material with good properties of tuft bond,flexibility, Velcro, etc. The polymer made above was sent to alaboratory to run a GPC (gell permeation chromatography) for molecularweights. The molecular weight was determined to be 12,579 with apolydispersity of 4.64.

The embodiments have been described with reference to particularlypreferred embodiments and examples. Those skilled in the art willappreciate that various modifications may be made to the embodimentswithout significantly departing from the spirit and scope thereof.

What is claimed is:
 1. A method of making a polymer comprising:providing a condensation polyester comprising a plurality of constituentmonomers and having a first molecular weight; providing a modifyingmonomer comprising more than two reactive groups having a hydroxyl,wherein the modifying monomer is capable of participating intransesterification reactions, has a molecular weight of less than 1500Daltons, and is not one of the constituent monomers; and withoutdepolymerizing the condensation polyester into its constituent monomers,transesterifying the modifying monomer with a predetermined amount ofthe condensation polyester, wherein said transesterifying produces afinal polymer having a second molecular weight that is greater than thefirst molecular weight.
 2. The method of claim 1, wherein thecondensation polyester is polyethylene terephthalate.
 3. The method ofclaim 1, wherein the condensation polyester is polyethylene naphthalate.4. The method of claim 1, wherein the modifying monomer is anethoxylate.
 5. The method of claim 1, wherein the final polymer is apolyol.
 6. The method of claim 5, further comprising reacting the polyolwith an isocyanate to produce a polyurethane.
 7. The method of claim 1,further comprising applying a vacuum during the step oftransesterifying.
 8. The method of claim 1, further comprising reactingthe final polymer with an anhydride to produce an acid-terminatedpolymer.
 9. The method of claim 1, wherein the condensation polyester isa recycled material.
 10. The method of claim 1, wherein the step ofproviding a modifying monomer comprises providing a plurality ofunreacted modifying monomers.
 11. The method of claim 1, wherein thetransesterification step comprises providing a plurality of stagedadditions of the condensation polyester.
 12. A method of making apolymer comprising: providing a condensation polyester having aplurality of constituent monomers; providing a modifying monomercomprising more than two reactive groups having a hydroxyl, that is notone of the constituent monomers; and without depolymerizing thecondensation polyester into its constituent monomers, transesterifyingthe modifying monomer with a predetermined amount of the condensationpolyester, wherein the transesterification is carried out for a periodof time of less than about 5 hours, and at a temperature of from about200° C. to about 290° C., wherein said transesterifying produces a finalpolymer.
 13. The method of claim 12, wherein the condensation polyesteris a recycled material.
 14. The method of claim 12, wherein the step ofproviding a modifying monomer comprises providing a plurality ofunreacted modifying monomers.
 15. The method of claim 12, wherein thetransesterification step comprises providing a plurality of stagedadditions of the condensation polyester.
 16. The method of claim 12,wherein the condensation polyester is polyethylene terephthalate. 17.The method of claim 12, wherein the condensation polyester ispolyethylene naphthalate.
 18. The method of claim 12, wherein themodifying monomer is an ethoxylate.
 19. The method of claim 12, whereinthe polymer is a polyol.
 20. The method of claim 19, further comprisingreacting the polyol with an isocyanate to produce a polyurethane. 21.The method of claim 12, further comprising applying a vacuum during thestep of transesterifying.
 22. The method of claim 12, further comprisingreacting the final polymer with an anhydride to produce anacid-terminated polymer.